1. Field of the Invention
This invention relates to a new belt tensioner and to a new actuator for such a belt tensioner as well as to new methods of making such a belt tensioner and such an actuator.
2. Prior Art Statement
It is known to provide a belt tensioner for an endless transmission belt construction arranged to move in a certain path, the tensioner comprising a support means, an arm pivotly mounted to the support means, a pulley rotatably carried by the arm for being disposed in engagement with the belt construction, and an actuator carried by the support means and having opposed ends, the actuator having a movable piston projecting out of one of the opposed ends thereof for being in engagement with the arm to pivot the arm in a direction to urge the pulley into the belt construction as the piston is extended outwardly from the one of the opposed ends of the actuator, the actuator having spring means therein that is operatively associated with the piston for urging the piston outwardly, the actuator having a rotatable shaft means that is operatively interconnected to the spring means and that is provided with opposite end means one of which is operatively interconnected to the piston, the actuator having a casing provided with an internal recess means therein that receives the other of the opposite end means of the shaft means therein, the recess means having end surface means, the spring means being adapted to rotate the shaft means to extend the piston while the other end means of the shaft means rotates in the recess means and bears against the end surface means thereof. For example, see the U.S. patent to Mitchell et al, U.S. Pat. No. 4,938,735.
It is also known to utilize thrust washers between a rotating part and a stationary part, the thrust washer being disposed against a shoulder of one of the parts and having a projection of that part extending through the opening of the thrust washer. In addition, it is known to provide a thrust needle bearing washer between a pair of flat thrust washers. For example, see pages 418 and 419 of the Torrington Service Catalog of the Torrington Co. of Torrington, Conn. and having a copyright date of 1988.